Question

我试图开发一款2球拍游戏。我创建了2个矩形（作为球拍）。我尝试从键盘控制它们并使用 KeyListener 事件处理程序为此目的...当我运行我的程序有时它工作，有时不。我想知道为什么它有效，但没有其他。这是我的代码。请告诉我哪里弄错了？感谢

import javax.swing.*;
import java.awt.*;

import java.awt.event.*;

public class Test implements KeyListener, ActionListener {

JFrame f;
MyPanel p; // Instance of MyPanel for left and right rackets
BallPanel bp; // Instance of BallPanel for Bouisng ball
int x1, y1, x2, y2;
int x, y;

public Test(){
    f = new JFrame("2 Rackets Game");

    Container c = f.getContentPane();
    c.setLayout(new BorderLayout());

    x = 5; y = 10;

    p = new MyPanel();
    bp = new BallPanel();

    c.add(bp);
    c.add(p);

    f.setSize(600, 400);
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    p.addKeyListener(this);
    p.setFocusable(true);

    Timer t = new Timer(5, this);
    t.start();
    }


public void keyTyped(KeyEvent e) {/*_______*/}
    int speed = 30;

public void keyPressed(KeyEvent e) {
    if(e.getKeyCode() == KeyEvent.VK_W){
        p.mY1 -= speed;
    }
    if(e.getKeyCode() == KeyEvent.VK_S){
        p.mY1 += speed;
    }

    if(e.getKeyCode() == KeyEvent.VK_UP){
            p.mY2 -= speed;
    }
    if(e.getKeyCode() == KeyEvent.VK_DOWN){
        p.mY2 += speed;
    }
   p.repaint();
}


public void keyReleased(KeyEvent e) {/*_______*/}

public void actionPerformed(ActionEvent e){
    if (f.getWidth()-25 == bp.mX){
        x = -5;
    }
    if (f.getHeight()-50 == bp.mY){
        y = -2;
    }
    if(bp.mX == 0){
        x = 5;
    }
    if(bp.mY == 0){
        y = 2;
    }
    bp.mX += x;
    bp.mY += y;

    bp.repaint();
}

 public static void main(String arg[]){
    Test t = new Test();
}

} Screenshot of Layout

Alos这里是“MyPanel”类的代码（用于在屏幕上绘制矩形）

import javax.swing.*;
import java.awt.*;

public class MyPanel extends JPanel {
// variables used to draw rectangles at different locations
int mX1  = 20;
int mY1 = 120;

int mX2 = 560;
int mY2 = 120;
// overriding paintComponent method
public void paintComponent(Graphics g){
    super.paintComponent(g);

    Graphics2D g2 = (Graphics2D)g;
    g2.setColor(Color.BLUE);
    // Left Racket
    g2.fillRect(mX1, mY1, 5, 80);
    //Right Racket
    g2.fillRect(mX2, mY2, 5, 80);
}

}

java KeyListener不能正常工作

0 个答案: